Maxim公司的MAX77503是同步1.5A 94%效率降壓DC疍C轉換器，工作輸入電壓3V到14V，輸出電壓在0.8V到5V間通過I2C串口可調，每步50mV，主要用在2電池／3電池高密度電源，手持鋰+／鋰離子電池供電設備，無人機，HD照相機和筆記本電腦。本文介紹了MAX77503主要特性和優勢，框圖和多種應用電路，以及評估板MAX77503 EVK優勢和特性，電路圖，材料清單和PCB設計圖。

　　1.5A buck converter with 94% efficiency for 2-cell/3-cell battery applications

　　The MAX77503 is a synchronous 1.5A step-down DCDCconverter optimized for portable 2-cell and 3-cell battery-operated and USB-C applications. The converter operateson an input supply between 3V and 14V. Outputvoltage is adjustable between 0.8V and 5V in 50mV stepsthrough an I2C serial interface or 1.55V to 99% of the supplyvoltage with external feedback resistors. Factory-programmeddefault voltages of 1.2V， 1.8V， and 3.3V are offeredto reduce component count for common rails. Thedevice features a low-IQ SKIP mode which allows excellentefficiency at light loads.

　　Dedicated enable and power-OK pins allow simple hardwarecontrol. An I2C serial interface is optionally used forfull configuration and control for dynamic voltage scalingand system power optimization.

　　Built-in undervoltage lockout （UVLO）， output active discharge，cycle-by-cycle current limit， thermal shutdown，and short-circuit protection ensure safe operation underabnormal operating conditions.

　　The MAX77503 is available in a 12-bump， 0.4mmpitch wafer-level package （WLP）。

　　MAX77503主要特性和優勢：

　　● 1.5A Single Channel Buck Regulator

　　● 3V to 14V Input Voltage Range

　　● 0.8V to 99%VSUP Output Voltage Range

　　? 0.8V to 5V I2C Programmable in 50mV Steps

　　? 1.55V to 99%VSUP with External FeedbackResistors

　　? 1.2V， 1.8V， or 3.3V Factory Preset Options

　　● High-Efficiency， Low-IQ Extends Battery Life

　　? 94% Peak Efficiency at 7.4VSUP， 3.3VOUT （2520Inductor）

　　? 9μA IQ （12VSUP， 1.8VOUT Internal FeedbackVersion）

　　? Selectable Light-Load SKIP and Forced-PWMModes

　　● 1MHz or 550kHz Fixed-Frequency Switching

　　● Hardware or Software Control

　　? Enable Input and Power-OK Output Pins

　　? Optional I2C Full Control Interface

　　● Protection Features

　　? Cycle-by-Cycle Inductor Peak Current Limit

　　? Short-Circuit Hiccup Mode， UVLO， and ThermalShutdown Protections

　　? 1ms Default Soft-Start

　　● Small Size

　　? 1.85mm x 1.4mm （0.7mm max. height） WLP

　　? 12-Bump， 0.4mm Pitch， 3 x 4 Array

　　MAX77503應用：

　　● 2-cell/3-cell High Power Density Supplies

　　● Portable Li+/Li-ion Battery Powered Devices

　　● Drones， HD Cameras， and Notebook Computers

　　● Space-Constrained Portable Electronics

　　圖1.MAX77503簡化應用電路

　　圖2.MAX77503外部反饋電路

　　圖3.MAX77503內部反饋電路，3.3V工廠默認

　　圖4.MAX77503內部反饋電路，1.8V工廠默認

　　圖5.MAX77503內部反饋電路，1.2V工廠默認

　　評估板MAX77503 EVK

　　The MAX77503 evaluation kit （EV kit） is a fully assem-bled and tested PCB that demonstrates the MAX77503 synchronous step-down （buck） converter. The EV kit is a step-down voltage regulator circuit using MAX77503 that is capable of 3V to 14V input， 1.5A continuous load， and output voltage adjustable between 0.8V and 5V （internal feedback options） or 1.55V and 99% of the input voltage （external feedback option）。

　　The EV kit features a dual-range electronic load that allows easy evaluation of loading use cases for the buck converter circuit. Steady-state， transient， or random load profiles can be programmed.

　　A USB-to-I2C translator circuit allows a Windows?-based PC to run a graphical user interface （GUI） for easy control of the MAX77503 registers as well as the on-board electronic load.

　　評估板MAX77503 EVK優勢和特性：

　　Proven PCB Reference Design and Layout

　　Easy to Use Simple Hardware Control： Jumpers and Test Points for EN， BIASEN， and POK

　　GUI Drives I2C Interface for Optional Software Control

　　Fully Assembled and Tested

　　USB to I2C Converter Allows for Easy Communication Windows-Based Software GUI Controls Registers

　　Level Translator （MAX3395） Allows for Adjusting I2C Bus Voltage from 1.8V to 3.3V

　　On-Board Electronic Load Emulates System Loading Steady-State， Transient， and Random Modes

　　圖6.評估板MAX77503 EVK外形圖

　　圖7.評估板MAX77503 EVK頂層視圖

　　圖8.評估板MAX77503 EVK底層視圖

　　圖9.評估板MAX77503 EVK簡化框圖

　　圖10.評估板MAX77503 EVK電路圖（1）

　　圖11.評估板MAX77503 EVK電路圖（2）

　　圖12.評估板MAX77503 EVK電路圖（3）

　　圖13.評估板MAX77503 EVK電路圖（4）

　　評估板MAX77503 EVK材料清單：

　　圖14.評估板MAX77503 EVK PCB設計圖：頂層絲印

　　圖15.評估板MAX77503 EVK PCB設計圖：頂層

　　圖16.評估板MAX77503 EVK PCB設計圖：內層2

　　圖17.評估板MAX77503 EVK PCB設計圖：內層3

　　圖18.評估板MAX77503 EVK PCB設計圖：底層

　　圖19.評估板MAX77503 EVK PCB設計圖：底層絲印

　　詳情請見：

　　https://datasheets.maximintegrated.com/en/ds/MAX77503.pdf

　　和https://datasheets.maximintegrated.com/en/ds/MAX77503AEVKIT-MAX77503B33EVKIT.pdf

　　MAX77503.pdf

　　MAX77503AEVKIT-MAX77503B33EVKIT.pdf